A conventional axle assembly of a motor vehicle comprises a differential gear and a pair of drive shaft assemblies penetrating both sides thereof. A solid annular spacer is provided between a side bearing assembly and a differential carrier. The drive shafts are ordinarily disposed within the axle shaft tubes.
Normally in operation, lubricant from the differential carrier penetrates the axle shaft tubes due to the splashing of the lubricant by rotation of a differential ring gear, or by other means.
When axle assemblies are of full floating type, the wheel ends do not require lubrication. Therefore, the lubricant entrapped inside the axle tubes should be returned to a carrier bowl. For this purpose, the carrier bowl of conventional design is formed with a cast-in drain-back channel facing downward.
Alternatively, when axle assemblies are of semi-floating type, the wheel ends require adequate lubrication. In this case, it is desirable to keep certain amount of lubricant inside the axle shaft tubes. For this purpose, the carrier bowl is formed with the cast-in drain-back channel facing upward that allows lubricant to be trapped in the axle tube bores.
This requires two different variations of differential carriers: for full-floating type axle assemblies and for semi-floating type axle assemblies each provided with the cast-in drain-back channel, however positioned differently.